Increased QT variability in patients with anorexia nervosa--an indicator for increased cardiac mortality?

Myocardial mechanics and cardiac biomarkers in adults with severe anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is associated with left ventricular (LV) atrophy and unexplained sudden death. Myocardial mechanics have not been well studied in adults with AN. Whether LV mass or illness duration, markers of AN severity, correlate with abnormal strain imaging is unknown.

METHODS

We performed a prospective study among patients hospitalized with severe AN (n = 29) [body mass index (BMI) < 14.5 kg/m2] and sex/age-matched controls (n = 16) (BMI > 18.5 kg/m2). LV ejection fraction (LVEF) was calculated via modified-biplane method and LV mass was derived using the truncated ellipsoid formula. Apical 2-, 3-, and 4-chamber images were used to generate regional strain mapping and global longitudinal strain (GLS). N-terminal brain natriuretic peptide (NT-proBNP) levels were measured and linear regression was used to determine independent predictors of strain.

RESULTS

Mean LVEF did not differ (65% ± 6.0 vs. 62% ± 4.4, p = 0.06), but LV mass was substantially reduced (61.6 ± 16.8 vs. 97.6 ± 19.1 g, p < .0001). GLS was similar (- 20.6 ± 3.8 vs. - 20.9 ± 2.8, p = 0.82), however, the basal strain was worse (-18.7 ± 4.8 vs. -21.9 ± 4.1, p = 0.03). Lower LV mass was associated with worsening GLS (r = - 0.40, p = 0.003), but not among controls (p = 0.89). Median (IQR) NT-proBNP (pg/ml) was higher in patients with AN [141 (59-257) vs. 35.5 (21-56.5) p = 0.0007]. Both increasing NT-proBNP and illness duration were associated with worsening strain patterns in AN (both p = .001).

CONCLUSIONS

While LVEF and GLS did not differ, regional strain variation was noted among patients with AN. Elevated NT-proBNP may reflect increased wall tension from LV atrophy. Whether strain heterogeneity can identify patients with AN, at risk for sudden death, requires further study.

Cardiac abnormalities determined by tissue Doppler imaging and arrhythmias in adolescents with anorexia nervosa

BACKGROUND

Anorexia nervosa has a prevalence of 0.5-3% in adolescents, placing this population at increased risk of cardiac anomalies including arrhythmias, pericardial effusion, and myocardial dysfunction. Our objective is to describe cardiovascular anomalies observed by tissue Doppler imaging in patients with anorexia nervosa.

METHODS

We retrospectively reviewed electrocardiogram, Holter, and echocardiography findings in 28 patients diagnosed with anorexia nervosa.

RESULTS

Electrocardiogram was abnormal in 71% of patients with sinus bradycardia observed in 57%. Holter confirmed sinus bradycardia without significant pauses. Prolonged QTc, low voltage, and ectopic beats were each seen in 14% of patients. Wenckebach atrioventricular block was observed in one patient. Supraventricular or ventricular tachycardia was not observed. Echocardiography showed structurally normal heart in all patients. Pericardial effusion was seen in 7.1% of patients and left ventricular mass was decreased in 10.7%. Mean ejection fraction was 0.73 and mean fractional shortening was 38.4%. Tissue Doppler imaging revealed systolic or diastolic dysfunction in four patients with e', a', and s' velocities in the lateral and septal basal segments more than two standard deviations below the mean. Two patients had decreased left ventricular mass but no significant difference in disease duration from the group. Basal segment velocities below one standard deviation were also observed in an additional seven patients.

CONCLUSION

A trend for decreased tissue Doppler imaging velocities was seen in 25.0% of patients, while significant systolic and diastolic dysfunction was seen in 14.3% of patients, associated with a significant reduction in left ventricular mass and independent of disease duration.

Caloric Restriction and Cardiovascular Health: the Good, the Bad, and the Renin-Angiotensin System

Much excitement exists over the cardioprotective and life-extending effects of caloric restriction (CR). This review integrates population studies with experimental animal research to address the positive and negative impact of mild and severe CR on cardiovascular physiology and pathophysiology, with a particular focus on the renin-angiotensin system (RAS). We also highlight the gaps in knowledge and areas ripe for future physiological research.

Autonomic Nervous System Function in Anorexia Nervosa: A Systematic Review

Background: Autonomic nervous system (ANS) dysfunction has been suggested to contribute to the high prevalence of cardiovascular complications in individuals with anorexia nervosa (AN), yet has not been thoroughly investigated. The current review aimed to synthesize the evidence of basal ANS function in individuals with a current diagnosis of AN and those with a previous diagnosis who had achieved weight restoration, as compared to controls. Methods: A systematic review of nine databases was conducted and studies that were published in a peer-review journal, in English, that included at least one assessment of ANS function in individuals with a current or previous diagnosis of AN were selected. Forty-six studies were included with a total of 811 participants with a current diagnosis of AN and 123 participants with a previous diagnosis of AN. Results: ANS function was assessed through heart rate variability (n = 27), orthostatic challenge, blood pressure variability or baroreflex sensitivity (n = 11), adrenergic activity (n = 14), skin conductance level (n = 4), and pupillometry (n = 1). Individuals with AN demonstrated increased parasympathetic activity and decreased sympathetic activity, suggestive of autonomic dysregulation. Following weight restoration, autonomic function trended toward, or was equivalent to, control levels. Discussion: Autonomic dysregulation is indicated through a range of assessments in individuals with AN. Future investigations should utilize a variety of assessments together in order to conclusively establish the nature of autonomic dysfunction in AN, and following extended weight restoration. Moreover, investigation into the co-occurrence of ANS function and cardiovascular risk is required.

Cortical thinning and associated connectivity changes in patients with anorexia nervosa

Structural brain abnormalities are a consistent finding in anorexia nervosa (AN) and proposed as a state biomarker of the disorder. Yet little is known about how regional structural changes affect intrinsic resting-state functional brain connectivity (rsFC). Using a cross-sectional, multimodal imaging approach, we investigated the association between regional cortical thickness abnormalities and rsFC in AN. Twenty-two acute AN patients and twenty-six age- and gender-matched healthy controls underwent a resting-state functional magnetic resonance imaging scan and cognitive tests. We performed group comparisons of whole-brain cortical thickness, seed-based rsFC, and network-based statistical (NBS) analyses. AN patients showed cortical thinning in the precuneus and inferior parietal lobules, regions involved in visuospatial memory and imagery. Cortical thickness in the precuneus correlated with nutritional state and cognitive functions in AN, strengthening the evidence for a critical role of this region in the disorder. Cortical thinning was accompanied by functional connectivity reductions in major brain networks, namely default mode, sensorimotor and visual networks. Similar to the seed-based approach, the NBS analysis revealed a single network of reduced functional connectivity in patients, comprising mainly sensorimotor- occipital regions. Our findings provide evidence that structural and functional brain abnormalities in AN are confined to specific regions and networks involved in visuospatial and somatosensory processing. We show that structural changes of the precuneus are linked to nutritional and functional states in AN, and future longitudinal research should assess how precuneus changes might be related to the evolution of the disorder.

Heart rate variability as a biobehavioral marker of diverse psychopathologies: A review and argument for an "ideal range"

Heart rate variability (HRV), a measure of the variability in intervals between subsequent heart beats, is now widely considered an index of emotion regulatory capacity and the ability to adapt flexibly to changing environmental demands. Abnormalities in HRV are implicated in a host of psychopathologies, making it a potentially powerful transdiagnostic biobehavioral change mechanism in treatment interventions. While most mental illnesses are associated with low HRV, eating disorders have been linked to elevated HRV. We examined 62 research articles on HRV in psychopathology to test the hypothesis that there is an "ideal range" of HRV that predicts optimal functioning. Relationships between symptom severity and parameters that quantify HRV were examined graphically. More extreme time-domain HRV measures, both high and low, were associated with psychopathology, whereas healthy controls displayed mid-range values. Findings preliminarily support the hypothesis that there is an "ideal range" of HRV that could be targeted in biofeedback interventions.

T-wave morphology among medically treated patients with Anorexia Nervosa

Anorexia nervosa (AN) has the highest rate of mortality of any psychiatric disorder, and cardiovascular complications occur in up to 80% of patients with AN and account for up to 30% of mortality. A controversy exists as to whether patients with AN are prone to develop electrocardiographic abnormalities related to repolarization. We aim to study previously unexplored T wave morphology markers in medically-treated patients with AN. Fifty-eight patients with AN (32 with restricting type and 26 with binge-eating/purging type) and 82 healthy controls were included in the study. ECGs were conducted under strict conditions and total cosine R-to-T (TCRT) and T-wave morphology dispersion (TMD) were computed according to accepted standards for a random beat and for an averaged beat. Forty-six AN patients were hospitalized (79.3%) during the study for a mean duration of 1.5 ± 1.1 months. AN patients had comparable QTc, TCRT, mean TMD, TMDpre, TMDpost and TCRTc values to those of healthy adults. Flattened T wave occurred slightly more often among AN patients than in controls (1.57 ± 1.23 leads affected compared with 1.11 ± 0.80 leads, respectively, p = 0.017). QTc, TCRT and TMD parameters' values were unaffected by the clinical type of AN. In conclusion, weight-restored AN patients are characterized by T wave flattening, but normal other T wave morphology parameters, which seemingly reflects an overall low risk of repolarization-associated ventricular arrhythmias. Long-term follow-up studies should be conducted to evaluate the prognostic significance of these novel repolarization markers in untreated patients or early in the refeeding phase.

Role of Neuroendocrine, Immune, and Autonomic Nervous System in Anorexia Nervosa-Linked Cardiovascular Diseases

Anorexia nervosa represents a severe mental disorder associated with food avoidance and malnutrition. In patients suffering from anorexia nervosa, cardiovascular complications are the main reason leading to morbidity and mortality. However, the origin and pathological mechanisms leading to higher cardiovascular risk in anorexia nervosa are still unclear. In this aspect, the issue of exact pathological mechanisms as well as sensitive biomarkers for detection of anorexia nervosa-linked cardiovascular risk are discussed. Therefore, this review synthesised recent evidence of dysfunction in multiple neuroendocrine axes and alterations in the immune system that may represent anorexia nervosa-linked pathological mechanisms contributing to complex cardiovascular dysregulation. Further, this review is focused on identification of non-invasive biomarkers for the assessment of increased cardiovascular risk in anorexia nervosa that can be linked to a clinical application. Complex non-invasive assessment of cardiovascular autonomic regulation—cardiac vagal control (heart rate variability), sympathetic vascular activity (blood pressure variability), and cardiovascular reflex control (baroreflex sensitivity)—could represent a promising tool for early diagnosis, personalized therapy, and monitoring of therapeutic interventions in anorexia nervosa particularly at a vulnerable adolescent age.

Heart rate variability as a biomarker for anorexia nervosa: A review

OBJECTIVE

Anorexia nervosa (AN) typically begins in early adolescence and other than weight status has few reliable biomarkers. Early diagnosis is a critical prognostic factor, but this can be clinically challenging. Heart rate variability (HRV), the beat-by-beat variance in heart rate (HR), may provide a unique assessment for the presence of AN because it has clinical utility as a biomarker of cardiac autonomic control in various populations (e.g., athletes, the aged, those with cardiovascular diseases, etc.). We present a review of the literature examining HRV in those with AN.

METHOD

Relevant publications were selected from PubMed using the search terms 'anorexia nervosa AND (HR OR HRV)'. Twenty papers were selected and reviewed.

RESULTS

The majority of studies suggest that those with AN have markedly and consistently elevated HRV compared to controls, even greater than among young athletes. However, no studies have explored HRV as a biomarker for AN.

DISCUSSION

Future studies on HRV should elucidate its role as a diagnostic biomarker for AN as well as its responsiveness with serial measurement to track response rates and predict relapse.

Persistent Renin-Angiotensin System Sensitization Months After Body Weight Recovery From Severe Food Restriction in Female Fischer Rats

Background Prior exposure to periods of severe food restriction (sFR) is associated with increased risk of developing hypertension and cardiovascular disease later in life. Methods and Results To investigate the mechanism of these long-term adverse effects of sFR, 4-month-old female Fischer rats were divided in 2 groups and maintained on a normal diet ad libitum (control) or on an sFR diet with 60% reduction in daily food intake for 2 weeks that resulted in a 15% reduction in body weight. After the 2-week sFR period ended, both groups received normal chow ad libitum for 3 months. Within 2 weeks after refeeding was initiated in the sFR group, body weight was restored to control levels; however, plasma angiotensinogen (1.3-fold; P<0.05), Ang-[1-8] (2.0-fold; P<0.05), and angiotensin-converting enzyme activity (1.1-fold; P<0.01) were all elevated 3 months after refeeding. Angiotensin type 1 receptor activity was also increased as evidenced by augmented pressor responses to angiotensin-[1-8] (P<0.01) and depressor responses to the angiotensin type 1 receptor antagonist, losartan (P<0.01) in the sFR group. Conclusions These results indicate that sensitization of the renin-angiotensin system persisted months after the sFR period ended. These findings may have implications for women who voluntarily or involuntarily experience an extended period of sFR and thus may be at increased risk of developing cardiovascular disease through sensitization of the renin-angiotensin system even though their body weight, mean arterial pressure, and heart rate appear normal.

Resting state heart rate variability in clinical and subthreshold disordered eating: A meta-analysis

OBJECTIVE

Research has demonstrated mixed results regarding the direction of the association between vagal activation and disordered eating. The current meta-analysis examined studies testing the link between resting-state heart rate variability indices of vagal activation (vmHRV), and both clinical and subthreshold disordered eating.

METHOD

A systematic search of the literature resulted in the inclusion of studies that were correlational (associations between HRV and disordered eating symptoms) and that examined group differences (e.g., control group vs. disordered eating group), for a total of 36 samples.

RESULTS

Findings indicated a small but reliable association of vmHRV with disordered eating, r = 0.12, indicating greater vagal activation in individuals with disordered eating compared to those with little or no disordered eating behavior. Moderation analyses identified predictors of the vmHRV/disordered eating association. Bulimia nervosa was found to have a large, positive effect size with vmHRV, r = 0.60, which was significantly greater than all other types of disordered eating, Q _T = 10.74, p = .047. Compared to subthreshold disordered eating, clinical eating disorders demonstrated significant, persistent increased vagal activation with a medium, reliable effect size, r = 25, Q_T = 3.94, p = .045.

CONCLUSION

These insights contribute to an improved understanding of the pathophysiology in disordered eating.

Changes to the electrocardiogram during exercise in anorexia nervosa

BACKGROUND

Anorexia Nervosa (AN) is an eating disorder characterized by low body weight, distorted body image, and an intense fear of gaining weight. Electrocardiogram (ECG) changes, particularly in the QT interval, have been implicated in AN-associated sudden death but not well defined.

OBJECTIVES

To characterize QT interval changes during exercise in anorexia nervosa.

METHODS

The QT interval was evaluated in a prospective cohort undergoing structured exercise. Patients from the St. Paul's Hospital Provincial Adult Tertiary Eating Disorders Program underwent a 6-minute modified exercise test protocol. A single lead ECG patch recording device was used to record a Lead I equivalent, due to challenges applying standard ECG monitoring in subjects with low body mass. Heart rate (HR) and QT interval were assessed.

RESULTS

Eighteen eating disorder patients (16 female) completed testing (age 31 ± 12 years, BMI 16.5 ± 3.8 kg/m²). Patients were compared to age- and sex-matched healthy controls. HR was similar between patients and controls (baseline: 65 (55-70)bpm vs. 69 (53-73)bpm, p = 0.83; maximum: 110 (94-139) bpm vs. 108 (93-141) bpm, p = 0.96; end recovery: 62 (54-68) bpm vs. 66 (55-75) bpm, p = 0.39). QTc intervals were similar between groups at baseline (381 ± 17 ms vs. 381 ± 46 ms, p = 0.93) and end recovery (397 ± 42 ms vs 398 ± 42 ms, p = 0.91). However, AN patients demonstrated QTc prolongation while controls showed QTc shortening at maximum HR (426 ± 70 ms vs. 345 ± 59 ms, p = 0.001).

CONCLUSION

Low level exercise HR increases are similar between AN patients and controls, but the QTc interval fails to shorten, which may explain the increased arrhythmic risk in AN.

QTc Interval and Risk of Cardiac Events in Adults With Anorexia Nervosa: A Long-Term Follow-Up Study

BACKGROUND

The literature contains several cases of anorexia nervosa (AN) patients with prolonged QTc interval. However, the risk of prolonged QTc interval is controversial and the risk of cardiac events in AN patients has yet to be investigated.

METHODS

We estimated the difference in mean QTc interval and relative risk of borderline prolonged QTc (>440 ms) and prolonged QTc (>460 ms) between 430 adult women AN patients and 123 healthy controls using 3 correction formulas. In a follow-up study, we estimated the risk of a primary end point (a composite of ventricular tachycardia, aborted cardiac arrest, and cardiac arrest) in AN patients compared with a population-based cohort derived from the Danish Civil Register.

RESULTS

Mean QTc for AN patients was 408 ms (Hodges), 402 ms (Fridericia), and 399 ms (Bazett). Hodges' found a slightly increased mean QTc (6.8 ms, 95% confidence interval, 1.6-12.0; P=0.01) and percentage with QTc >440 ms in AN patients (relative risk, 3.7, 95% confidence interval, 1.4-10.3; P=0.01), not observed with Fridericia's and Bazett's formulas. There was no difference in the risk of QTc >460 ms between AN patients and healthy controls. During a median follow-up of 10.1 years, AN patients had an increased risk of the primary end point compared with the population-based cohort (hazard ratio, 10.4, 95% confidence interval, 2.6-41.6; P=0.001). However, absolute numbers were small with cumulative incidences of 0.5% and 0.07%, respectively, after 10 years. No events occurred in any AN patient with QTc >440 ms. All-cause mortality was also significantly increased in AN patients compared with the population-based cohort (hazard ratio, 11.2, 95% confidence interval, 5.1-24.5; P<0.001).

CONCLUSIONS

Overall, there was no difference in mean QTc interval or risk of prolonged QTc between AN patients and healthy controls. However, AN patients had a notably increased all-cause mortality, as well as an increased risk of cardiac events, which was not related to the baseline QTc interval.

Arterial stiffness and haemodynamic regulation in adolescent anorexia nervosa versus obesity

Cardiovascular complications contribute to higher morbidity and mortality in patients with anorexia nervosa. We aimed to study biomarkers of cardiovascular risk in anorexic, normal-weight, and obese adolescents with focus on complex cardiovascular autonomic regulation and early arteriosclerotic damage. We examined 20 adolescent girls with anorexia nervosa, 20 obese girls, and 20 healthy normal-weight controls. Collected data: body composition analysis, 5 min recordings of R-R intervals and beat-to-beat blood pressure (BP), and arterial stiffness evaluated using cardio-ankle vascular index (CAVI). Evaluated parameters: beat-to-beat heart rate and BP variability, haemodynamic parameters (total peripheral resistance (TPR) cardiac output), CAVI, and anthropometric indices, including novel body roundness index (BRI). Adolescents with anorexia nervosa had increased CAVI associated with lower arterial constriction indexed by low-frequency band of BP variability compared with normal-weight peers (p = 0.03, p = 0.04, respectively) and obese adolescents (p < 0.01, p = 0.01, respectively). After normalization of CAVI and TPR by BRI, the relationship between CAVI and TPR was significant for all groups with the highest slope in the anorexia nervosa group (R² = 0.724, p < 0.01). This is the first study revealing early arteriosclerotic damage in anorexic girls with increased CAVI. Complex analysis of cardiovascular autonomic regulation, and early arteriosclerotic, hemodynamic, and anthropometric changes in spectrum anorexia nervosa, normal weight, and obesity could help to understand the mechanisms of increased cardiovascular risk in malnutrition. Novelty Girls with anorexia nervosa showed signs of early arteriosclerotic damage indexed by CAVI. Insufficient sympathetic cardiovascular control was found already in adolescents with anorexia nervosa. The effect of body composition on CAVI was best predicted by novel body roundness index.

Impact of Nutrition on Cardiovascular Function

The metabolic sources of energy for myocardial contractility include mainly free fatty acids (FFA) for 95%, and in lesser amounts for 5% from glucose and minimal contributions from other substrates such lactate, ketones, and amino acids. However, myocardial efficiency is influenced by metabolic condition, overload, and ischemia. During cardiac stress, cardiomyocytes increase glucose oxidation and reduce FFA oxidation. In patients with ischemic coronary disease and heart failure, the low oxygen availability limits myocardial reliance on FFA and glucose utilization must increase. Although glucose uptake is fundamental to cardiomyocyte function, an excessive intracellular glucose level is detrimental. Insulin plays a fundamental role in maintaining myocardial efficiency and in reducing glycemia and inflammation; this is particularly evident in obese and type-2 diabetic patients. An excess of F availability increase fat deposition within cardiomyocytes and reduces glucose oxidation. In patients with high body mass index, a restricted diet or starvation have positive effects on cardiac metabolism and function while, in patients with low body mass index, restrictive diets, or starvation have a deleterious effect. Thus, weight loss in obese patients has positive impacts on ventricular mass and function, whereas, in underweight heart failure patients, such weight reduction adds to the risk of heart damage, predisposing to cachexia. Nutrition plays an essential role in the evolution of cardiovascular disease and should be taken into account. An energy-restricted diet improves myocardial efficiency but can represent a potential risk of heart damage, particularly in patients affected by cardiovascular disease. Micronutrient integration has a marginal effect on cardiovascular efficiency.

Role of the Renin Angiotensin System in Blood Pressure Allostasis-induced by Severe Food Restriction in Female Fischer rats

Severe food restriction (FR) is associated with blood pressure (BP) and cardiovascular dysfunction. The renin-angiotensin system (RAS) regulates BP and its dysregulation contributes to impaired cardiovascular function. Female Fischer rats were maintained on a control (CT) or severe FR (40% of CT) diet for 14 days. In response to severe FR, BP allostasis was achieved by up-regulating circulating Ang-[1–8] by 1.3-fold through increased angiotensin converting enzyme (ACE) activity and by increasing the expression of AT₁Rs 1.7-fold in mesenteric vessels. Activation of the RAS countered the depressor effect of the severe plasma volume reduction (≥30%). The RAS, however, still underperformed as evidenced by reduced pressor responses to Ang-[1–8] even though AT₁Rs were still responsive to the depressor effects of an AT₁R antagonist. The aldosterone (ALDO) response was also inadequate as no changes in plasma ALDO were observed after the large fall in plasma volume. These findings have implications for individuals who have experienced a period(s) of severe FR (e.g., anorexia nervosa, dieters, natural disasters) and suggests increased activity of the RAS in order to achieve allostasis contributes to the cardiovascular dysfunction associated with inadequate food intake.

QT interval and dispersion in drug-free anorexia nervosa adolescents: a case control study

Long QT values have been reported in patients with anorexia nervosa of the restricting type (ANr) potentially increasing the risk of fatal arrhythmia, especially if psychotropic drug treatment is required. Nevertheless, the previous studies on this topic are biased by drug exposure, long disease durations, and small sample sizes. This study is aimed at assessing QTc and QTcd values in ANr adolescents with recent onset and drug free, as compared to subjects affected by psychiatric disorders other than ANr. We evaluated QTc and its dispersion (QTcd) in a population of 77 drug-free ANr female adolescents and compared to an equal number of healthy controls (H-CTRL) and pathological controls (P-CTRL, mixed psychiatric disorders). The QT determination was performed on a standard simultaneous 12-lead ECG in blind by a single experienced investigator. QTc was calculated by the Bazett's formula and QTcd was determined as the difference between the maximum and minimum QTc intervals in different leads. Only for ANr patients, clinico-demographic data, hormones, and electrolytes were obtained. QTc was slightly reduced in ANr patients (27.7 ms, < 10%, p < 0.0003) vs. controls, while QTcd was increased in P-CTRL (30%, p < 0.0003). Heart rate was significantly lower in ANr patients vs. controls (25%; p < 0.003). Tyroid hormones and serum potassium showed weak although significant positive correlations with QTc in ANr patients. QTcd displayed a weak negative correlation with the BMI percentile (r = - 0.262, p = 0.03). We reject the hypothesis that QTc and QTcd are increased in drug-free ANr adolescents with a relatively short-disease duration. Further studies are needed to understand if the previously reported increase might be related to other associated chronic disorders, such as hormonal or electrolyte imbalance.

Characterization and correlates of exercise among adolescents with anorexia nervosa and bulimia nervosa

OBJECTIVE

To characterize exercise behaviors among adolescents with anorexia nervosa (AN), atypical AN, or bulimia nervosa (BN), and determine associations between exercise and medical risk.

STUDY DESIGN

Cross-sectional electronic medical records of all patients evaluated by the Eating Disorder Program at Stanford between January 1997 and February 2011 were retrospectively reviewed.

RESULTS

1,083 subjects (961 females, 122 males; mean age 15.6) met eligibility criteria. Most patients (89.7%) reported exercise (mean 7.0 h per week over mean 5.4 days per week) prior to presentation. Running (49.9%), calisthenics (40.7%), walking (23.4%), soccer (20.9%), and swimming (18.2%) were the most common exercises; a majority (60.6%) reported team sport participation. Males were less likely to report team exercise (p = .005). Bradycardia (heart rate <50) at presentation was associated with team sport participation (adjusted odds ratio [AOR] 1.66, 95% confidence interval [CI] 1.02-2.72) and hours of exercise per week (AOR 1.05, 95% CI 1.02-1.09), controlling for diagnosis, sex, age, duration of illness, rate of weight loss, and percent median body mass index (%mBMI).

DISCUSSION

Adolescents with AN, atypical AN, and BN reported high levels of exercise. Females reported more team sport participation. Greater exercise frequency and team sport participation were associated with bradycardia. Further studies assessing the relationship between exercise and bradycardia may help inform the medical management of adolescents with these eating disorders who are more physically active.

Cardiac autonomic function and vascular profile in subclinical hypothyroidism: Increased beat-to-beat QT variability

BACKGROUND

Patients with subclinical hypothyroidism (SH) may have higher incidence of coronary heart disease and autonomic dysfunction.

DESIGN OF THE STUDY

Prospective case control study.

AIM AND OBJECTIVES

To evaluate beat-to-beat QT variability and vascular stiffness in patients with SH compared to normal controls.

MATERIALS AND METHODS

We compared linear and nonlinear measures of cardiac repolarization liability using beat-to-beat QT intervals derived from the surface electrocardiogram during supine posture and vascular indices including pulse wave velocity and ankle-brachial index (ABI) during supine posture between female patients with SH and age- and sex-matched normal controls. Spectral analysis was done at very low frequency (LF) (0.003-0.04 Hz), Low frequency (LF) (0.04-0.15 Hz), and high frequency (HF) (0.15-0.4 Hz). The HF represents vagal regulation (parasympathetic) and LF represents both parasympathetic and sympathetic regulation.

RESULTS

We recruited 58 women with a mean age of 31.83 ± 8.9 years and 49 controls with mean age of 32.4 ± 9.9 years (P = NS). QT variability index (QTvi) was higher in cases compared to controls (P = 0.01). The ratio of LF/HF of R-R interval which is an index of sympathovagal tone was significantly more in cases compared to controls (P = 0.02). The difference in the left minus the right ABI was significant between cases and controls (P = 0.03).

CONCLUSIONS

The cases had lower parasympathetic activity as compared to controls, and there was a predominance of sympathetic activity in cases. QTvi may be an important noninvasive tool in this group of patients to study the risk of cardiovascular mortality.

QT interval variability in body surface ECG: measurement, physiological basis, and clinical value: position statement and consensus guidance endorsed by the European Heart Rhythm Association jointly with the ESC Working Group on Cardiac Cellular Electrophysiology

This consensus guideline discusses the electrocardiographic phenomenon of beat-to-beat QT interval variability (QTV) on surface electrocardiograms. The text covers measurement principles, physiological basis, and clinical value of QTV. Technical considerations include QT interval measurement and the relation between QTV and heart rate variability. Research frontiers of QTV include understanding of QTV physiology, systematic evaluation of the link between QTV and direct measures of neural activity, modelling of the QTV dependence on the variability of other physiological variables, distinction between QTV and general T wave shape variability, and assessing of the QTV utility for guiding therapy. Increased QTV appears to be a risk marker of arrhythmic and cardiovascular death. It remains to be established whether it can guide therapy alone or in combination with other risk factors. QT interval variability has a possible role in non-invasive assessment of tonic sympathetic activity.

Risk for prolonged QT interval and associated outcomes in children with early restrictive eating patterns

Aim This study aimed to describe the frequency of QTc prolongation in children with restrictive eating disorders early in the course of disease admitted for inpatient therapy, to determine the frequency of associated ventricular arrhythmia, and to evaluate the relationship between QTc interval and concomitant electrolyte abnormalities and rate of weight loss.

METHODS

This was a retrospective cohort study of patients aged 11-25 years with early restrictive eating disorders.

RESULTS

In all, 82 patients met the inclusion criteria (84% female). In total, 9.8% had prolonged QTc interval during hospitalisation. Patients with prolonged QTc had significantly higher resting heart rates (p=0.006), but there was no association with hypokalaemia (p=0.31), hypomagnesaemia (p=0.43), hypophosphataemia (p=1), or rate of weight loss (p=1).

CONCLUSION

Mild QTc prolongation in patients with restrictive eating disorders is not related to electrolyte abnormalities or rate of weight loss in this population, suggesting that investigation about other potential risk factors of prolonged QTc interval may be warranted.

Heart Rate Variability during Inpatient Psychosomatic Treatment - A Naturalistic Observational Study

OBJECTIVES

We tested the hypothesis that inpatient psychosomatic treatment would improve both psychological distress and autonomic dysfunction, indexed as heart rate variability (HRV).

METHODS

135 patients (mean age 47.2 years, 68.1% women) were enrolled. The most frequent diagnoses were somatoform disorders, adjustment disorders, major depression, eating disorders, and anxiety disorders.Mean duration of treatment was 21.8 ± 7.3 days. Complete HRV data were available on 105 patients.

RESULTS

At the beginning of the treatment, psychological distress correlated with the low frequency/ high frequency ratio of HRV, indicating a shift of autonomic balance towards sympathetic predominance. Following treatment, psychological distress had improved, but parasympathetic activity was even lower. Tricyclic antidepressant use was associated with an increase in heart rate. No other associations between antidepressant use and autonomic function were observed.

CONCLUSIONS

Reductions of psychological distress may not be reflected by improved autonomic function. Studies on interventions that may improve both psychological distress and autonomic dysfunction are desirable.

Characterization of Myocardial Repolarization Reserve in Adolescent Females With Anorexia Nervosa

BACKGROUND

Patients with anorexia nervosa exhibit abnormal myocardial repolarization and are susceptible to sudden cardiac death. Exercise testing is useful in unmasking QT prolongation in disorders associated with abnormal repolarization. We characterized QT adaptation during exercise in anorexia.

METHODS AND RESULTS

Sixty-one adolescent female patients with anorexia nervosa and 45 age- and sex-matched healthy volunteers performed symptom-limited cycle ergometry during 12-lead ECG monitoring. Changes in the QT interval during exercise were measured, and QT/RR-interval slopes were determined by using mixed-effects regression modeling. Patients had significantly lower body mass index than controls; however, resting heart rates and QT/QTc intervals were similar at baseline. Patients had shorter exercise times (13.7±4.5 versus 20.6±4.5 minutes; P<0.001) and lower peak heart rates (159±20 versus 184±9 beats/min; P<0.001). The mean QTc intervals were longer at peak exercise in patients (442±29 versus 422±19 ms; P<0.001). During submaximal exertion at comparable heart rates (114±6 versus 115±11 beats/min; P=0.54), the QTc interval had prolonged significantly more in patients than controls (37±28 versus 24±25 ms; P<0.016). The RR/QT slope, best described by a curvilinear relationship, was more gradual in patients than in controls (13.4; 95% confidence interval, 12.8-13.9 versus 15.8; 95% confidence interval, 15.3-16.4 ms QT change per 10% change in RR interval; P<0.001) and steepest in patients within the highest body mass index tertile versus the lowest (13.9; 95% confidence interval, 12.9-14.9 versus 12.3; 95% confidence interval, 11.3-13.3; P=0.026).

CONCLUSIONS

Despite the absence of manifest QT prolongation, adolescent anorexic females have impaired repolarization reserve in comparison with healthy controls. Further study may identify impaired QT dynamics as a risk factor for arrhythmias in anorexia nervosa.

QT variability improves risk stratification in patients with dilated cardiomyopathy

Recently it could be demonstrated that systolic and diastolic blood pressure variability (BPV) as well as segmented Poincare plot analysis (SPPA) contribute to risk stratification in patients suffering from dilated cardiomyopathy (DCM). The aim of this study was to improve the risk stratification applying a multivariate technique including QT variability (QTV). We enrolled and significantly separated 56 low risk and 13 high risk DCM patients by nearly all applied BPV and QTV methods, but not with traditional heart rate variability analysis. The optimum set of two indices calculating the multivariate discriminate analysis (DA) included one BPV index calculated by symbolic dynamics method (DBP(Shannon)) and one index calculated from QTV (QTV(log)) achieving an area under the receiver operating characteristics curve (AUC) of 92%, sensitivity of 92.3% and specificity of 89.3%. Performing only electrocardiogram analysis, the optimum multivariate approach including indices from segmented Poincaré plot analysis and QTV still achieved a remarkable AUC of 88.3%. Increasing the number of indices for multivariate DA up to three, we achieved an AUC of 95.7%, sensitivity of 100% and specificity of 85.7% including one clinical, one BPV and one QTV index. Summarizing, we identified DCM patients with an increased risk of sudden cardiac death applying QTV analysis in a multivariate approach.

Anorexia nervosa - medical complications

In contrast to other mental health disorders, eating disorders have a high prevalence of concomitant medical complications. Specifically, patients suffering from anorexia nervosa (AN) have a litany of medical complications which are commonly present as part of their eating disorders. Almost every body system can be adversely, affected by this state of progressive malnutrition. Moreover, some of the complications can have permanent adverse effects even after there is a successful program of nutritional rehabilitation and weight restoration. Within this article we will review all body systems affected by AN. There is also salient information about both, how to diagnose these medical complications and which are the likely ones to result in permanent sequelae if not diagnosed and addressed early in the course of AN. In a subsequent article, the definitive medical treatment for these complications will be presented in a clinically practical manner.

Insular dysfunction and descending pain inhibition in anorexia nervosa

OBJECTIVE

Reduced perception of pain is a well-established phenomenon in patients with anorexia nervosa (AN). We tested the hypothesis that altered processing of pain within the insula might account for reduced perception of pain.

METHOD

Heat pain thresholds were obtained in nineteen patients with AN and matched controls. Thereafter, a thermode was used to deliver thermal painful stimuli to the right arm during functional magnetic resonance imaging (fMRI) measurements. Stimuli were initiated for 10 s from a baseline resting temperature (32°C) to three different levels (37, 42, 45°C).

RESULTS

Significantly increased heat pain thresholds were observed in patients. A stronger activation during heat pain perception was found in the left posterior insula in controls. In contrast, higher levels of activity were shown in the ipsilateral pons in patients when compared to controls. In patients, we found a significant interrelation between the depression score (Beck depression inventory) and heat pain activations.

CONCLUSION

We suggest that reduced activity in the left posterior insula might contribute to increased pain thresholds in patients, while increased activations in the right anterior insula and pons mirror augmented sympathetic modulation putatively related to amplification of adrenergic descending pain inhibition. In addition, pain thresholds and brain activations were influenced by disease-inherent depressed mood.

Normal late ventricular potentials in hospitalized patients with eating disorders

OBJECTIVE

Eating disorders, in particular anorexia nervosa (AN), are associated with cardiovascular complications and risk of arrhythmias. In a recent published study, it was found that patients with eating disorders, especially those affected by bulimia nervosa (BN) and a history of AN have abnormal late ventricular potentials (LPs). LPs are electrocardiographic markers used in detecting abnormal depolarization and increased risk of arrhythmias. Given the paucity of knowledge regarding the affects of eating disorders on cardiac depolarization, our aim was to further explore LPs in patients with eating disorders.

METHOD

The study group included 30 hospitalized patients with eating disorders (14 with AN, 10 with BN with no history of AN, and 6 with BN and history of AN). Signal averaged electrocardiography was conducted on all patients using the Frank corrected orthogonal lead system.

RESULTS

No patient with either eating disorder tested positive for LPs.

DISCUSSION

Hospitalized patients with eating disorders, medically monitored and treated for several weeks, had normal serum electrolytes, started to normalize their weight, and did not appear to be prone to arrhythmias associated with abnormal depolarization. The prognostic significance of LPs in risk stratification of patients with eating disorders should be further evaluated by large cohort studies and longer follow-up studies.

[The processing of pain in psychiatric diseases]

The perception and processing of pain is disturbed in many psychiatric diseases. Some diseases are known to show decreased perception of pain (e.g. borderline personality disorder), while others are associated with augmented pain perception (e.g. alcohol and drug dependence). The close relationship between psychiatric diseases and pain is most probably caused by aberrant processing of pain in brain structures, known to be involved in psychiatric disorders as well. Aberrant perception and processing of pain in patients with anorexia nervosa (AN) will be used to demonstrate this close relationship. Dysfunction within the insula has been suggested to account for many features of AN and might contribute to reduced pain perception. Moreover, it might lead to increased adrenergic descending inhibition associated with increased sympathetic modulation. Thus, pain research might be able to alter our view on autonomic regulation, which is putatively associated with increased cardiac mortality of the disease.

Factors influencing QT prolongation in patients hospitalized with severe anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) carries the highest mortality of any psychiatric disorder largely attributable to sudden cardiac death and suicide. Controversy exists regarding the underlying mechanism of cardiac risk, whether QT prolongation is a consistent feature of the disorder and whether repolarization varies by disease severity. Some of the uncertainty may relate to a lack of standardized electrocardiography (ECG). To date, studies have not utilized centrally adjudicated digital ECG, and most have relied on the Bazett formula for rate-correction, which is suboptimal at the extremes of heart rate often observed in AN.

METHODS

We evaluated a hospitalized cohort of medically compromised, very-low-body mass index (BMI) AN patients. The QT interval was measured with high-precision calipers by a single, blinded electrophysiologist and rate corrected (QTc) using the Fridericia formula. Anatomically corrected left ventricular (LV) mass and resting energy expenditure (REE) were calculated as proxies for disease severity. Proportions exceeding categorical thresholds for QTc prolongation and correlations between admission QTc and disease severity were performed.

RESULTS

Among 19 patients, mean BMI was 12.3 kg/m(2), and 95% were female. The majority (68%) of patients were receiving QT-prolonging drugs. Four patients (21%) had QTc prolongation. Two of these patients (10.5%) exceeded the 500 ms threshold for marked QTc-prolongation, though each had concomitant factors contributing to delayed repolarization. The QTc interval was not significantly correlated with LV mass, LV mass index, BMI or REE.

CONCLUSIONS

Although delayed cardiac repolarization was observed among a medically compromised cohort of patients with anorexia nervosa, the QTc interval was not a reliable correlate of disease severity despite digital ECG adjudication and optimal rate correction.

QT variability among weight-restored patients with anorexia nervosa

OBJECTIVE

Anorexia nervosa (AN) may be complicated by cardiac arrhythmias and sudden death. A single study reported an increased QT variability index (QTVI), a marker for cardiac arrhythmogenicity, in AN patients. The aim of the current study was to further evaluate repolarization dynamics in a large cohort of patients with AN without electrolyte abnormalities and to evaluate previously unreported repolarization dynamics parameters.

METHODS

Forty-three AN patients and 45 age- and sex-matched controls were included in the study. Twenty-nine AN patients were hospitalized for a mean time of 1.5±1.1 months. The rest were ambulatory AN patients. Electrocardiograms were conducted under strict standards. QT variability index, normalized QT variability (QTVN) and power spectral analysis of QT dynamics were conducted with designated computer software.

RESULTS

None of the patients had an electrolyte imbalance. Although mean QT was higher in AN patients compared with controls, QTc results were similar following corrections for RR interval. There was no significant difference in QTVI, QTVN and power spectral analysis parameters among groups. The results of QTVI and QTVN were comparable to those previously published for healthy individuals. During 3 years of follow-up, no patient developed arrhythmias or suddenly died.

CONCLUSIONS

Medically treated AN patients who gained weight and had normal serum electrolytes appeared to have normal QTc and QT variability indexes, reflecting a nonincreased risk for cardiac arrhythmias. We suggest that weight normalization, medical treatment and lack of electrolyte abnormalities are responsible in part for these results. Further evaluation of the prognostic significance of QTVI and QTVN in AN is warranted.

Heart rate variability as a measure of cardiac autonomic function in anorexia nervosa: a review of the literature

OBJECTIVE

Patients with anorexia nervosa (AN) exhibit a wide range of autonomic system disturbances; these patients have also high mortality risk due to cardio-vascular complications. Origin and pathogenesis of such changes are not absolutely clear.

METHODS

Relevant publications were drawn from PUBMED using the keywords 'anorexia nervosa' AND 'autonomic'. Fifty two abstracts were identified and screened for papers that measured the state of autonomic regulation by means of analysis of heart rate variability either during 24-hour electrocardiography (ECG) monitoring or during a short-term laboratory test. Studies selected were analysed for the number of patients included, the presence and quality of control groups, gender, age and body mass index (BMI) of patients, type of AN as well as methods used to determine heart rate variability (HRV).

RESULTS

Twenty papers on HRV in patients with anorexia were identified and analysed, revealing three distinct positions regarding changes of autonomic nervous system (ANS) functions in patients with AN. The majority of papers identified parasympathetic/sympathetic imbalance with parasympathetic dominance and decreased sympathetic modulation; others could not replicate these findings, but instead described sympathetic dominance; finally a group of papers could not identify any autonomic differences in comparison to control samples. We conclude that in its current state of analysis HRV may not be suitable for routine assessment of ANS function in AN patients but rather remains a research tool.

Reduced cardio-respiratory coupling after treatment with nortriptyline in contrast to S-citalopram

OBJECTIVE

Major depressive disorder is associated with increased cardiac mortality. A decrease in vagal modulation related to reduced heart rate variability might contribute to increased mortality among many other factors. We sought to examine the hypothesis that nortriptyline treatment will be associated with a decrease in heart rate variability and coupling between heart rate and respiration compared to treatment with S-citalopram.

METHODS

Fifty-two patients suffering from major depression were included. Patients were examined unmedicated in the acute stage and after 5weeks of treatment. Twenty-six were reinvestigated after they received S-citalopram and 26, after nortriptyline. We used non-linear measures of heart rate variability and also a novel measure to examine cardio-respiratory coupling to assess cardiac vagal modulation.

RESULTS

There were significant decreases of non-linear measures of heart rate variability in the nortriptyline group in addition to reduced cardio-respiratory coupling in comparison to the group of patients that received S-citalopram. We observed a significant association between the severity of the disease and vagal withdrawal prior to treatment.

CONCLUSIONS

These findings indicate that S-citalopram influences autonomic modulation on different regulatory levels to a lesser extent than nortriptyline. Our results have implications for treatment of patients with depression as some of them may already have a higher risk for cardiovascular mortality. In addition, it underlines the beneficial use of SSRIs in patients with cardiac diseases.